The practice of sharing and re-using syringes without adequate sterilization between successive users is a major contributor to the transfer of Human Immunodeficiency Virus (HIV) and Hepatitis with subsequent severe repercussions for the sufferer and at a high cost to society for supporting and providing medical attention to sufferers. Furthermore, health professionals may be exposed to used syringes which can lead to inadvertent needlestick injuries and possible exposure to infective pathogens or other contaminants.
One solution to these problems has been the introduction of single-use syringes for use in hospitals, medical centres and vaccination programs and also for use by intravenous drug users. However, such syringes typically comprise a specialized barrel and/or needle assembly (e.g. a retractable needle assembly) which are not readily amenable to modification or adaptation to allow filtering of injectable fluids during filling of the syringe or to replace bent or burred needles.
With particular regard to the need for filtering, an injectable substance may include potentially dangerous impurities such as particulate material that can cause abscesses, oedema and/or embolism in a user. Because some injectable drugs may be obtained illicitly, the purity and quality of the injectable drug is often poor. This is particularly a problem with drugs of addiction such as heroin, which may be due to impurities in the drug itself, or in substances combined with the drug to improve injectability. To address this problem a filter may be used with the syringe to ensure that fluid withdrawn into the syringe through the filter is rendered free of particulate matter and other impurities. An example of such a filter is the Sterifilt™ filter produced by Apothicom. In some countries this is a legal requirement of needle exchange programs for intravenous drug users.